class/System.ComponentModel.Composition/src/ComponentModel/System/ComponentModel/Composition/CompositionResult.cs

   1 // -----------------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 // -----------------------------------------------------------------------
   4 using System;
   5 using System.Collections.Generic;
   6 using System.Diagnostics.CodeAnalysis;
   7 using System.Linq;
   8 using Microsoft.Internal.Collections;
   9 using System.ComponentModel.Composition.Hosting;
  10
  11 namespace System.ComponentModel.Composition
  12 {
  13     internal struct CompositionResult
  14     {
  15         public static readonly CompositionResult SucceededResult = new CompositionResult();
  16         private readonly IEnumerable<CompositionError> _errors;
  17
  18         public CompositionResult(params CompositionError[] errors)
  19             : this((IEnumerable<CompositionError>)errors)
  20         {
  21         }
  22
  23         public CompositionResult(IEnumerable<CompositionError> errors)
  24         {
  25             this._errors = errors;
  26         }
  27
  28         public bool Succeeded
  29         {
  30             get { return this._errors == null || !this._errors.FastAny(); }
  31         }
  32
  33         public IEnumerable<CompositionError> Errors
  34         {
  35             get { return this._errors ?? Enumerable.Empty<CompositionError>(); }
  36         }
  37
  38         public CompositionResult MergeResult(CompositionResult result)
  39         {
  40             if (this.Succeeded)
  41             {
  42                 return result;
  43             }
  44             if (result.Succeeded)
  45             {
  46                 return this;
  47             }
  48             return MergeErrors(result._errors);
  49         }
  50
  51         public CompositionResult MergeError(CompositionError error)
  52         {
  53             return MergeErrors(new CompositionError[] { error });
  54         }
  55
  56         public CompositionResult MergeErrors(IEnumerable<CompositionError> errors)
  57         {
  58             return new CompositionResult(this._errors.ConcatAllowingNull(errors));
  59         }
  60
  61         public CompositionResult<T> ToResult<T>(T value)
  62         {
  63             return new CompositionResult<T>(value, this._errors);
  64         }
  65
  66         public void ThrowOnErrors()
  67         {
  68             ThrowOnErrors(null);
  69         }
  70
  71         public void ThrowOnErrors(AtomicComposition atomicComposition)
  72         {
  73             if (!this.Succeeded)
  74             {
  75                 if (atomicComposition == null)
  76                 {
  77                     throw new CompositionException(this._errors);
  78                 }
  79                 else
  80                 {
  81                     throw new ChangeRejectedException(this._errors);
  82                 }
  83             }
  84         }
  85     }
  86 }